JP2000319638A - Antistatic agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antistatic agent excellent in compatibility with a base material such as a thermoplastic resin and capable of developing its antistatic effect for a long-term even when used in a small amount, which agent comprises an ester of a copolymer of an α-olefin of a specified number of carbon atoms with maleic anhydride with an alcohol/alkylene oxide adduct. SOLUTION: The copolymer used is one of a 18-52C α-olefin with maleic anhydride and has a weight-average molecular weight of, desirably, 1,500-30,000, more desirably, 5,000-15,000. The α-olefin/maleic anhydride ratio of the copolymer is, desirably, 98/2 to 72/28, more desirably, 95/5 to 82/18 by weight. The alkylene oxide used is, desirably, a 2-4C one, especially desirably, ethylene oxide or propylene oxide. The ratio, total number of carbon atoms/total number of oxygen atoms, in the alkylene oxide adduct is desirably 2/1 to 4/1, particularly desirably, 2.1/1 to 2.9/1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an antistatic agent, and more particularly to an antistatic agent suitable for a kneading type for a resin.

[0002]

2. Description of the Related Art Generally, thermoplastic resin materials are used in a wide range of fields due to their excellent characteristics. However, since they are electrically insulating, they are easily charged by static electricity. As a result, dust adheres to molded products. When used for a case or a part of an electric / electronic device or the like, the appearance may be impaired, and the discharge may cause malfunction of the device or breakage of the IC. For this reason, in recent years, research to enhance the antistatic property of thermoplastic resins has been actively pursued.

Conventionally, in order to impart an antistatic property to a thermoplastic resin, a method of adding a surfactant type antistatic agent is generally used. In this case, a short-term antistatic property after molding is used. Although it has excellent properties, it is difficult to maintain the antistatic property for a long period of time, and there is a problem that the antistatic agent on the surface of the molded article drops due to friction or washing with water, and the performance is rapidly lowered. In addition, if a large amount of antistatic agent is added for the purpose of maintaining the antistatic property over a long period of time, with the passage of time, an excessive amount of the antistatic agent bleeds out to the surface of the molded product, causing stickiness, On the contrary, there is a disadvantage that dust easily adheres.

A method of kneading a conductive inorganic material, such as carbon fiber or carbon black, into a thermoplastic resin has also been put to practical use in order to impart durability. However, the conductive inorganic material is black. Therefore, there is a problem that the color tone of the plastic using this is limited to black.

On the other hand, recently, as a method for solving the above-mentioned problems, a method has been developed in which a hydrophilic polymer is added to a thermoplastic resin to have a persistent antistatic effect. Examples of the hydrophilic polymer include polyethylene glycol and polyethylene diamine, which have poor compatibility with plastics, easily cause bleed-out, and have problems in appearance quality and washing resistance. Also, JP-A-58-11836 discloses that
A method of adding an antistatic effect by adding a polyetheresteramide is disclosed, and further disclosed in JP-A-07-278.
No. 530 discloses a method of adding an antistatic effect by adding a copolymer of maleic anhydride and a maleic ester of a compound containing a polyethylene oxide chain. However, in the methods described in these publications, a sufficient antistatic property cannot be exhibited unless a large amount is added, and there is a problem that the mechanical properties of plastics are reduced by adding a large amount. . Further, there is a problem that the compatibility with the resin is insufficient, particularly the compatibility with the olefin resin is poor, and the appearance is poor due to delamination or the strength of the molded body is reduced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems and the current state of the prior art, and is intended to solve the problem. Provide an antistatic agent that has excellent compatibility, does not deteriorate the physical properties and appearance of the resin, and exhibits antistatic properties over a long period of time with a small amount of addition, and also has excellent washing resistance. The purpose is to:

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned conventional problems and the like, and as a result, have found that a copolymer of a specific α-olefin and maleic anhydride and a specific alkylene oxide adduct are obtained. The inventors have found that the esterified product can be used as the antistatic agent for the above purpose, and have completed the present invention. That is, the antistatic agent of the present invention,
It is characterized by comprising an esterified product of a copolymer of an α-olefin having 18 to 52 carbon atoms and maleic anhydride and an alkylene oxide adduct of alcohol.

[0008]

Embodiments of the present invention will be described below in detail. The antistatic agent of the present invention has 18 to 5 carbon atoms.
A copolymer of α-olefin of 2 and maleic anhydride;
Characterized in that it comprises an esterified product of an alcohol and an alkylene oxide adduct,
Excellent compatibility with the thermoplastic resin, etc. as the base material, without deteriorating the physical properties and appearance of the resin, and exhibiting antistatic properties for a long time with a small amount of addition, Will also be excellent.

The above-mentioned esterified product serving as the antistatic agent of the present invention is obtained by reacting a copolymer of an α-olefin having 18 to 52 carbon atoms and maleic anhydride with an alkylene oxide adduct of one or more alcohols. It can be manufactured by doing. The weight average molecular weight of the above copolymer is preferably from 1500 to 30,000, more preferably from 5,000 to 15,000. By setting the weight average molecular weight of the copolymer to 1500 to 30000, the compatibility with a thermoplastic resin or the like becomes extremely excellent, and the antistatic property is exhibited over a long period of time by adding a smaller amount of the copolymer. In addition, an antistatic agent having even better washing resistance can be obtained.

In the present invention, α in the above copolymer
-The weight ratio of olefin / maleic anhydride is 98/2 to 2
72/28, more preferably 9/28.
5/5 to 82/18. The α-olefin, which is a component of the copolymer, must have 18 to 52 carbon atoms, and preferably has 30 to 52 carbon atoms.
When the carbon number of the α-olefin is less than 18, the compatibility with the resin becomes insufficient, and when the carbon number exceeds 52, the reactivity with the alkylene oxide adduct of alcohol becomes insufficient, which is not preferable. . The copolymer in the present invention can be produced by copolymerizing at least one kind selected from the above-mentioned α-olefins having 18 to 52 carbon atoms with maleic anhydride. For example, a copolymer of an α-olefin having 30 to 50 carbon atoms and maleic anhydride [“Diacarna PA30” manufactured by Mitsubishi Chemical Corporation, a weight ratio of α-olefin / maleic anhydride is 91/9, Weight average molecular weight: 9000-10000, saponification value: 100 mgK
OH / g, maleic anhydride content: 8.8% by weight), the same applies hereinafter).

In the present invention, the alcohol of the alkylene oxide adduct includes, for example, methanol, ethanol, propanol, butanol, hexanol,
Octanol, lauryl alcohol, stearyl alcohol, ethylene glycol, propylene glycol, hexanediol, butylene glycol, glycerin, erythritol, pentaerythritol, sorbitol and the like, preferably, methanol, ethanol,
Ethylene glycol, propylene glycol and glycerin, more preferably dihydric to trihydric alcohols such as ethylene glycol, propylene glycol and glycerin.

[0012] The alkylene oxide may have 2 to 2 carbon atoms.
4, and among them, ethylene oxide and propylene oxide are particularly preferable.

Further, the alkylene oxide adduct is
A single adduct of one type of alkylene oxide, a block adduct of two or more alkylene oxides, or a random adduct may be used.
To 100, more preferably 9 to 80.

As the alkylene oxide adduct of the alcohol, one kind may be used alone, or two or more kinds may be used in combination. Especially, the ratio of the total carbon number / total oxygen number of the alkylene oxide adduct is preferably from 2/1 to 4/1, and particularly preferably from 2.1 / 1 to 2.9 / 1. When the ratio of the total number of carbon atoms / the total number of oxygen atoms is less than 2/1, the compatibility with a thermoplastic resin or the like is inferior, and when the ratio exceeds 4/1, the antistatic performance is inferior. Is not preferred.

Preferred as the alkylene oxide adduct of a monohydric alcohol is an alkylene oxide adduct of methanol, and an ethylene oxide adduct having a number average molecular weight of 200 to 2,000 and / or a number average molecular weight of 200 to 1
It is a propylene oxide adduct of 5000 and / or a block and / or random adduct of ethylene oxide and propylene oxide having a number average molecular weight of 200 to 15,000. When the number average molecular weight exceeds 15,000, the reactivity with the copolymer is poor, and when the number average molecular weight is less than 200, the antistatic performance is poor. Also, when an ethylene oxide adduct having a number average molecular weight of more than 2,000 is used, the antistatic performance becomes poor.

Preferred as alkylene oxide adducts of polyhydric alcohols are dihydric to trihydric alcohols, for example, alkylene oxide adducts of ethylene glycol and / or glycerin, having a number average molecular weight of 20.
It is an ethylene oxide adduct of 0 to 2000 and / or a propylene oxide adduct having a number average molecular weight of 200 to 15,000 and / or a block or random adduct of ethylene oxide and propylene oxide having a number average molecular weight of 200 to 15,000. Particularly, it is particularly preferable to use two or more alkylene oxide adducts of dihydric and trihydric alcohols in combination. When the number average molecular weight exceeds 15,000, the reactivity with the copolymer is poor, and when the number average molecular weight is less than 200, the antistatic performance is poor. Also, when an ethylene oxide adduct having a number average molecular weight of more than 2,000 is used, the antistatic performance is inferior.

In the present invention, the esterification reaction between the copolymer of an α-olefin having 18 to 52 carbon atoms and maleic anhydride and an adduct of an alkylene oxide with an alcohol causes the copolymer and the adduct to coexist. It is not particularly limited as long as it is esterified by heating in a heated state. For example, a heating reaction vessel equipped with a stirring device such as a stirring blade,
The esterification reaction may be performed in an extruder, a Banbury mixer, a kneader, or the like. In this esterification reaction, a solvent may be used if necessary. However, a method in which the reaction is carried out in a molten state without using a solvent does not require a step of removing the solvent, and is more economical and preferable. Further, at the time of this reaction, if necessary, it may be diluted with a thermoplastic resin, that is, may be prepared as a master batch. As the diluting resin, a thermoplastic resin containing the antistatic agent of the present invention and / or a resin having good compatibility with the thermoplastic resin is preferable.

When the reaction is carried out in a reaction vessel equipped with the above-mentioned stirring device, the reaction temperature is preferably from 120 to 200 ° C.,
The temperature is more preferably 140 to 180 ° C. The reaction time is
It is preferably 10 to 500 minutes, more preferably 30 to 3 minutes.
60 minutes. Further, the reaction pressure is not particularly limited, but is preferably from 0.1 to 400 mmHg, and more preferably from 0.1 to 150 mmHg.

When a single-screw or twin-screw extruder used for kneading or molding the above-mentioned resin or the like is used, the reaction temperature is preferably from 150 to 250 ° C, particularly preferably from 170 to 230 ° C. The reaction pressure is not particularly limited, but is preferably 0.1 to 400 mmHg, and particularly preferably 0.1 to 150 mmHg.

In the above esterification reaction, the charge ratio (mixing ratio) of the copolymer and the adduct is such that the molar ratio of the terminal hydroxyl group in the adduct to the maleic anhydride group constituting the copolymer is 0. It is preferable to set so as to be 1 to 3, and particularly preferably, it is in the range of 0.1 to 2.8. If the molar ratio is less than 0.1, the antistatic performance will be poor. If the molar ratio exceeds 3, the compatibility with the resin will be poor, which is not preferable.

In the present invention, it is preferable that the antistatic agent further contains a metal salt of an organic sulfonic acid in addition to the esterified product. Examples of the metal salt of the organic sulfonic acid include, for example, paraffin sulfonic acid, dodecyl sulfonic acid, tetradecyl sulfonic acid, hexadecyl sulfonic acid, alkyl sulfonic acid such as octadecyl sulfonic acid, methyl ester of α-sulforauric acid, α-sulfomyristin Acid methyl ester, α-sulfopalmitic acid methyl ester, α-sulfostearic acid methyl ester, etc., α-sulfo fatty acid methyl ester, dodecylbenzenesulfonic acid, dodecyldiphenylethersulfonic acid, etc. sodium salt, potassium salt, etc.
Lithium salts, calcium salts, magnesium salts, zinc salts and the like can be mentioned. Among them, preferred are sodium or potassium salts of paraffinsulfonic acid, and particularly preferred are sodium or potassium salts of paraffinsulfonic acid having 6 to 22 carbon atoms.

The metal salt of the organic sulfonic acid is blended usually in an amount of 0 to 100 parts by weight, preferably 0.1 to 50 parts by weight, and particularly preferably 100 to 100 parts by weight of the esterified product. It is in the range of 0.5 to 10 parts by weight. Further, the metal salt of the organic sulfonic acid is preferably blended in an amount of usually 0 to 5 parts by weight, preferably 0.01 to 3 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Preferably it is in the range of 0.1 to 1.5 parts by weight.

The shape of the antistatic agent of the present invention is not particularly limited, and examples thereof include powder, flake, granule, block, pellet, wax, and paste.

The antistatic agent of the present invention can be used, for example, as follows. That is, the antistatic agent of the present invention,
After uniformly mixing the pellets or the powdery thermoplastic resin with a Henschel mixer or the like, or preparing an antistatic agent-added compound with an extruder or the like, supplying the mixture or the compound to various molding machines to a predetermined amount. Process into the shape of It is also possible to prepare a masterbatch to which the antistatic agent is added at a high concentration and dilute the masterbatch before use.

The antistatic agent of the present invention comprises a thermoplastic resin 10
Usually, 0.1 to 30 parts by weight, preferably 0.3 to 15 parts by weight, particularly preferably 0.5 to 15 parts by weight with respect to 0 parts by weight.
Used in parts by weight. If the compounding amount of the antistatic agent is
If the amount is less than 0.1 part by weight, sufficient antistatic properties may not be obtained.
An effect commensurate with the amount can be expected, and conversely, the physical properties of the thermoplastic resin may be impaired.

When the above-mentioned esterified product is diluted with a thermoplastic resin during the esterification reaction, the shape of the antistatic agent of the present invention may be, for example, pellets,
Powder, flake, granule, block and the like can be mentioned. Further, when the above esterified product is diluted with a thermoplastic resin during the esterification reaction, the antistatic agent of the present invention can be used, for example, as follows. That is,
The antistatic agent of the present invention is uniformly mixed with a pellet or powdered thermoplastic resin using a Henschel mixer or the like, or after preparing an antistatic agent-added compound using an extruder or the like, the mixture or the compound is variously mixed. It is supplied to a molding machine and processed into a predetermined shape. It is also possible to prepare a masterbatch to which the antistatic agent is added at a high concentration and dilute the masterbatch before use. In the case of the esterification reaction, when the esterified product is diluted with respect to 100 parts by weight of the thermoplastic resin so as to be in the range of 0.1 to 30 parts by weight, the esterified product is supplied as it is to various molding machines and is supplied to a predetermined molding machine. May be processed.

When the esterified product is diluted with a thermoplastic resin at the time of the esterification reaction, the antistatic agent of the present invention is added to 100 parts by weight of the thermoplastic resin including the thermoplastic resin used for the dilution. On the other hand, the esterified product is 0.1 to 3
0 parts by weight, preferably 0.3 to 15 parts by weight, particularly preferably 0.5 to 15 parts by weight.

In the present invention, examples of the type of thermoplastic resin to be used as an antistatic agent include polyethylene,
Polypropylene, acrylic resin, polystyrene, polyacrylonitrile, acrylonitrile / styrene copolymer resin (AS resin), styrene / methyl methacrylate copolymer resin (MS resin), vinyl chloride resin, acrylonitrile / butadiene / styrene copolymer heavy resin (ABS resin) , Polyethylene terephthalate, polyamide, polycarbonate and the like, and a blend of these resins may be used. Preferably, polyethylene,
Polypropylene is particularly desirable.

The antistatic agent of the present invention may contain various additives, if necessary, in addition to the esterified compound and the metal salt of organic sulfonic acid. For example, higher alcohols, fatty acid amides, lubricants such as fatty acid metal soaps, antioxidants,
UV absorbers, silicone derivatives, anti-blocking agents,
A coloring agent, a filler, a flame retardant, a release agent, an antibacterial agent, a fluidizing agent and the like can be used in combination. The mixing ratio of these additives is within a range that does not inhibit the function of the esterified product,
It is appropriately determined according to the type.

The thermoplastic resin composition containing the antistatic agent of the present invention can be prepared by press molding, injection molding, extrusion molding,
By a general plastic molding method such as blow molding and calender molding, it can be processed into various molded products including sheets and films.

[0031]

Next, the present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

First, antistatic agents a to c used in the examples of the present invention were produced according to Production Examples 1 to 3 below. (Production Example 1) A random addition product of ethylene oxide and propylene oxide of glycerin (hereinafter, referred to as “PEPG-1”, a number average molecular weight of 40) synthesized using a conventional method.
00, 25 parts by weight of ethylene oxide / propylene oxide = 14/86) and 50 parts by weight of polyethylene glycol (“PEG # 1000”, manufactured by Lion Corporation, number average molecular weight = 1000) were mixed, and a nitrogen atmosphere was added. After the temperature was raised to 120 ° C., 25 parts by weight of a copolymer of α-olefin and maleic anhydride (manufactured by Mitsubishi Chemical Corporation, “Diacarna PA30”) was gradually added, and the mixture was stirred and dissolved. Then, while removing generated water out of the system, 1
The mixture was stirred at 60 ° C. and 50 mmHg for 5 hours to obtain an esterified product (antistatic agent a). At this time, the molar ratio of the hydroxyl group contained in the alkylene oxide adduct of maleic anhydride / alcohol contained in the copolymer of α-olefin and maleic anhydride was 1 / 2.5.

(Production Example 2) Ethylene oxide of propylene glycol and a random adduct of propylene oxide (hereinafter referred to as “PEPG-2”), synthesized by a conventional method, having a number average molecular weight of 3100 and a weight ratio of ethylene oxide / propylene oxide. = 35/65) 30 parts by weight, and polyethylene glycol ("PEG # 1000") 4
An esterified product (antistatic agent b) was obtained in the same manner as in Production Example 1 except that 5 parts by weight was used. At this time, the molar ratio of the hydroxyl group contained in the alkylene oxide adduct of maleic anhydride / alcohol contained in the copolymer of α-olefin and maleic anhydride was 1 / 2.4.

(Production Example 3) An esterified product (antistatic agent c) was obtained in the same manner as in Production Example 1 except that the above-mentioned PEPG-1 was not added. At this time, the molar ratio of the hydroxyl groups contained in the alkylene oxide adduct of maleic anhydride / alcohol contained in the copolymer of α-olefin and maleic anhydride was 1 / 2.2.

(Examples 1 and 2) Melt flow rate 10
90 parts by weight of the polypropylene resin and 10 parts by weight of each of the antistatic agents a and b prepared in Production Example 1 or 2 were mixed using a Henschel mixer, and the mixture was kneaded using a twin-screw extruder. Thus, a strand cut pellet was prepared. Using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., model TS-150), the pellets were heated at a cylinder temperature of 195 ° C
To form a 76 mm × 76 mm × 1.6 mm plate sample.

Example 3 92.5 parts by weight of a polypropylene resin having a melt flow rate of 10 and 7.5 parts by weight of the antistatic agent c prepared in Production Example 3 were mixed using a Henschel mixer. The mixture was formed into a plate-like sample in the same manner as in Examples 1 and 2.

Example 4 89.4 parts by weight of a polypropylene resin having a melt flow rate of 10, 9 parts by weight of the antistatic agent a prepared in Production Example 1, and sodium paraffin sulfonate ("Hostapur" manufactured by Clariant Japan KK)
SAS-93 ", average carbon number: 15) and 0.6 parts by weight were mixed using a Henschel mixer, and the mixture was formed into a plate-like sample in the same manner as in Examples 1 and 2.

Comparative Example 1 99.4 parts by weight of a polypropylene resin having a melt flow rate of 10 and 0.6 of sodium paraffin sulfonate (“Hostapur SAS-93”)
Parts by weight were mixed using a Henschel mixer, and the mixture was formed into a plate-like sample in the same manner as in Examples 1 and 2.

Comparative Example 2 A polypropylene resin pellet having a melt flow rate of 10 was prepared without using an antistatic agent.
A plate-like sample was formed in the same manner as in Examples 1 and 2.

Examples 1 to 4 and Comparative Example 1 obtained above
Using each of the plate samples of Nos. 1 to 3, a water resistance test was performed before, after, and after frictional water washing according to the following test methods, and the resistivity of the sample surface was measured and the stain resistance was evaluated. The results are shown in Table 1 below.

The resistivity of the sample surface was measured using a resistance measuring device (manufactured by Mitsubishi Yuka Co., Ltd., Hirester H-210). The stain resistance was determined by placing the sample in a dirt chamber, blowing the toner for a copying machine for 2 minutes, observing the state of carbon adhesion, and visually determining the degree of contamination by the following evaluation criteria. Evaluation criteria: ○: no contamination △: slight contamination ×: considerable contamination

(Water resistance test method) (1) Before water rinsing The sample was stored in a constant temperature room at 20 ° C. and a relative humidity of 60% for one day, and the surface resistivity of the sample was measured to judge the stain resistance. Was. (2) After Rinsing After placing the sample in a beaker and flowing tap water for 2 hours, the tap water was replaced with ion exchanged water. The sample was taken out of the beaker, air-dried, and stored in a constant temperature room at 20 ° C. and a relative humidity of 60% for one day. Then, the surface resistivity of the sample was measured to determine the stain resistance. (3) After rubbing with water After placing the sample in a beaker and flowing tap water for 1 hour, the surface was rubbed 40 times with a gauze containing tap water. After replacing tap water with ion-exchanged water, the sample was taken out of the beaker, air-dried, and placed in a constant temperature room at 20 ° C. and a relative humidity of 60%.
After storage for one day, the surface resistivity of this sample was measured to determine the stain resistance.

[0043]

[Table 1]

As is evident from the results in Table 1, Examples 1 to 4 of the present invention were compared with Comparative Examples 1 and 2 which were out of the scope of the present invention before, after and after frictional washing. Also in the washing resistance test, it was found that the sample surface resistance was low, the stain resistance was excellent, and the antistatic agent was excellent in the washing resistance.

[0045]

The antistatic agent of the present invention is excellent in compatibility with thermoplastic resins and the like, does not deteriorate the physical properties and appearance of the resin, and can be added to the antistatic agent for a long time by adding a small amount. It develops and is also excellent in washing resistance. Therefore, by using the antistatic agent of the present invention, various properties, particularly thermoplastic resin molded articles used for applications that come into contact with water, at low cost, easily, various properties possessed by the thermoplastic resin and the like. Excellent antistatic properties can be imparted over a long period of time without loss.

Claims (1)

[Claims] 1. An antistatic agent comprising an ester of a copolymer of an α-olefin having 18 to 52 carbon atoms and maleic anhydride, and an alkylene oxide adduct of an alcohol.